Method for improving foam stability of foaming detergent composition and improved stabilizers therefor



, 2,991,296 Patented July 4, 1961 2,991,296 METHOD FOR IMPROVING FOAM STABILITY OF FOAMING DETERGENT COMPOSITION AND HVIPROVED STABILIZERS THEREFOR Oscar L. Scherr, 4059 Perlita Ave., Los Angeles, Calif. No Drawing. Filed Feb. 26, 1959, Ser. No. 795,608 4 Claims. (Cl. 260-404) The present invention relates to novel foam stabilizers and detergents and to detergent or foaming compositions stabilized or improved by the incorporation thereof. It relates further to novel chemical compounds useful as foam stabilizers and detergents and to a method for the stabilization of foams by the incorporation of such materials into foaming detergent compositions. The invention relates further to foam stabilizers especially effective with anionic foaming agents.

Certain detergents and detergent compositions such as those containing soaps and/ or synthetic detergents or interface modifiers and particularly the anionic surface active agents, depend to a certain extent upon their ability to form at least a certain degree of foam, and the ability to maintain such foams for a sufiicient period of time to enable them to be effective in launderingcleaning and dishwashing and other dirt and grease removing applications. This is particularly important in the presence of grease since the maintenance of foam is important in facilitating the emulsification of the grease and in maintaining such emulsions in suspension. In order to improve the stability of foams, certain materials, which in themselves may or may not possess detergency, have been utilized, such as lauric monoisopropanolamide as described in U.S. Patent 2,757,143, or N-dodecyl acetamide as described in U.S. Patent 2,702,278.

Applicant has discovered novel chemical compounds which are highly effective as foam stabilizers, in foaming detergent compositions and particularly with anionic surface active agents, and which will maintain foam stability in the presence of substantial proportions of fat and grease.

It is, therefore, an object of the present invention to provide a novel chemical compounduseful as a foam stabilizing agent for foaming detergent compositions.

It is a further object of the invention to provide a foam stabilizer which Will maintain substantial foam stability in foaming detergent compositions in the presence of substantial proportions of grease and fat.

It is still a further object of the invention to provide an improved foaming detergent composition having substantial foam stability, particularly in the presence of oils, fats and grease.

It is yet another object of the product invention to greatly improve or enhance the foaming efficiency and stability as Well as the detergency, cleaning power, laundering properties and dishwashing utility of surface active agents commonly known as wetting agents or detergents, and especially the anionic surface active agents.

It is an additional object of the invention to provide a process for improving the foam stability of foaming detergents.

The above and other objects will become more fully apparent from a consideration of the. following specification:

Applicant has discovered that improved foam stabilizing agents may be obtained by the ethoxylation of the isopropanolamides of certain aliphatic carboxylic acids including certain-fatty acids and their alkyl esters, such as the .isopropanolamides of stearic, oleic, linoleic, palmi-ticand myristic acid and their alkyl esters, such as the methyl ester. The amides may be derived from the pure fatty acids or mixtures thereo f, orcommercial impure mixtures containing them, as well as directly from the oils or fats themselves such as the vegetable oils, castor oil, hydrogenated tallow or the like.

Foam stabilizers such as are now commonly being used for household detergents, both dry powdered, or flaked, and liquid, are primarily based on lauric acid or its methyl ester. The most commonly utilized stabilizers are the lauric isopropanolamide, known as LIPA and the lauric diethanol-amides, commonly known as LDA. These are efficient foam stabilizers and have a certain degree of detergency in themselves, however, they are not as effective as is desirable in the presence of substantial amounts of grease or greasy or oily soil, and hence are not completely satisfactory in dishwashing and other compositions; furthermore, these materials are fairly expensive, and lower cost, but at least equally effective or superior raw materials, would be greatly desired by the industry. p

In obtaining the fatty acids and their methyl esters from the fatty oils, such as cocoanut oil, the. high ends, namely the C14, 16 and 18 chain length fatty acids and their methyl esters are gradually accumulated as surplus materials without great value or utility. Although the lauric acid amides are substantially Water soluble and useful in the manufacture of paint stabilizers, the amides of the higher molecular weight fatty acids, such as stearic acid, are only slightly soluble in water and have no value as foam stabilizers or detergents in themselves. They are principally used as opacifiers and pearling agents in cosmetic products.

In accordance with applicants invention the novel products described are obtained by incorporating two or more ethylene oxide groups into an aliphatic carboxylic acid derivative of isopropanolamidqor into a mixture of such derivatives to' form a compound having the following structure:

where R is any aliphatic carboxylic acid radical having 13-17 or more carbon atoms and X=any whole number from 2 or higher, preferably from 2 to 20. These compounds are prepared by first preparing the isopropanolamide from monoisopropanol-amine and the fatty acids, their methyl esters, orthe corresponding oils. This is then ethoxylated by the addition of ethylene oxide to produce the desired novel product. od of preparation of thme compounds are as follows:

EXAMPLE A 23 mole of a mixture of methyl esters of fatty acids I (6325 grams) were reacted with 25.3 mols (1897.5 grams) The fatty acid esters wereof monoisopropanolamine. the still bottoms of cocoanut oil fattyacid methyl esters which had been hydrogenated and consisted essentially of 7% myristic acid ester, 45% palrnitic acid ester and 48% stearic acid ester. These still bottoms are low priced and are available in large supply, since they, have heretofore had no particular utility asbases or intermediates for chemical syntheses. For example they have been available at prices as low as 10 per 1b., at a time when C. and poured into a stainless steel pan. 'The prod Examples of the methuct was a hard, brittle, waxy cream-colored solid found to be monoisopropanolarnides of the corresponding mixed fatty acids.

EXAMPLE B 4.48 mols of the product of A (1424 grams) and 3 grams of KOH pellets were charged to a stainless steel autoclave, agitated and heated to 145 C., purged of air with nitrogen, and 8.96 mols (394 grams) of ethylene oxide added at such a rate that maximum pressure did not exceed 100 pounds. The temperature was maintained at 145 C. by means of cooling water circulated through a jacket around the autoclave and a coil internally thereof. After about 2 hours the reaction mixture was cooled to 100 C. and 6 cc. of glacial acetic acid added. The final product was a pale amber liquid which solidified to a soft paste on standing. The product was found to be the ethoxylated derivative of the fatty acid isopropanolamides from Example A, containing 2 mols of ethylene oxide per mol.

EXAMPLE C 3.23 mols (1026 grams) of the product of Example A were reacted with 19.36 mols of ethylene oxide in the presence of KOH as described in Example B. The product was the ethoxylated derivative of the fatty acid isopropanolamides from Example A containing 6 mols of ethylene oxide per mol.

EXAMPLE D 2.63 mols (835 grams) of the product of Example A, were reacted with 26.3 mols of ethylene oxide in the presence of KOH in the manner described in Example B, except that the maximum reaction temperature was 164 C.

The product was the ethoxylated derivative of the fatty acid isopropanolamides from Example A containing mols of ethylene oxide per mol.

Other ethoxylated derivatives containing other ratios of ethylene oxide were obtained in the same manner, such as the 1 mol ethoxylate, the 12 mol ethoxylate and the mol ethoxylate.

EXAMPLE E 3 mols of monoisopropanolamine lauric amide were reacted with 12 mols of ethylene oxide according to the procedure outlined in Example B. The final product was found to be the corresponding ethoxylated derivative having four mols of ethylene oxide per mol of compound.

EXAMPLE F 3 mols of monoisopanolamine stearic amide were reacted with 12 mols of ethylene oxide according to the procedure outlined in Example B. The final product was found to be the corresponding ethoxylated derivative having four mols of ethylene oxide per mol of compound.

Monoisopropanolamides of myristic acid, palmitic acid, oleic acid, and tall oil fatty acids, were prepared in the same manner as described above in Example A. The individual amides were then ethoxylated to produce ethylene oxide derivatives having from 2 to 20 mols of ethylene oxide added thereto. These were found to be superior foam stabilizers in the presence of grease as were the compounds derived from the mixed fatty acid derivatives reacted in Examples B to D inclusive, and had similar advantageous properties by comparison with LIPA or LDA.

The compounds produced in the above manner were evaluated as foam stabilizers in a series of experiments to determine effectiveness in foam stability and grease resistance by comparison with other known, commonly used eifective stabilizers heretofore utilized for these purposes. These comparisons were made by preparing standard foaming compositions, with and without known stabilizers, testing these for foam stability and grease resistance, and making the same tests after substituting the new stabilizing compound for those used in the standard compositions. The tests were carried out using a standard foam test in which 250 ml. of solution was placed in a 500 ml. cylinder and inverted 20 times to generate foam. The volume of foam was then measured and the measurement repeated at given time intervals to measure stability of the foam. Grease resistance was measured by carrying out the same procedure in the presence of successive 10 ml. additions of refined cotton seed oil, the cylinder being upended 20 times after each addition. The quantity of oil required to form a grease film on the glass was determined and this point taken as that at which the grease resistance of the foam had failed. The foaming ability and stability of the resultant foams were also measured at different time intervals. In general, if the foam volume declined substantially within 15 minutes of standing, it was considered that the foam stability in the presence of the varying amounts of grease is poor.

In each of the following examples comparisons were made using the following compounds:

LlPA Lauric isopropanolamide LDA Lauric diethanolamide Sl=-Ethoxylation product of Example A with 1 mol ethylene oxide S2=Ethoxylation product of Example B with 2 mols ethylene oxide S-4=Ethoxylation product of Example A with 4 mols ethylene oxide S-6:Ethoxylation product of Example C with 6 mols ethylene oxide S10=Etho-xylation product of Example D with 10 mols ethylene oxide S-12==Eth0xylati0n product of Example A with 12 mols ethylene oxide S-20=Ethoxylation product of Example A with 20 mols ethylene oxide L-4=Pr0duct of ethoxylation of Example E with 4 mols ethylene oxide S-4A=Product of ethoxylation of Example F with 4 mols ethylene oxide EXAMPLE I Formulation:

Foaming composition-Dodecyl benzene sulfonate Stabilizer concentration 2.5% Concentration of formulation in water 0.1%

Table 1 Foam stability Grease resistanceML refined cotton seed oil ML oil Foam to form stabigrease lizer Ini 5 15 film on tial min min. 10 20 30 40 glass ML ML ML N o rim-The asterisked figures in this and succeeding tables indicates that the foam remained stable for a longer period than 15 minutes. whereas the absence of the asterisk indicates that the foam stability declined or disappeared after 15 minutes.

The above comparisons clearly demonstrate that the initial foam formation and stability at 5 and 15 minute intervals using the new compounds is at least as good, and in some cases better, than using LIPA and LDA. In addition, grease resistance was definitely superior.

H I EXAMPLE II Table 4 Formulation:

Foaming composition20% dodcyl benzene S111- Foam stability Grease resistance'-MLrefi.ned

fonate cotton seed 011 ML oil I Foam to form Stabilizer concentration 2.5% 5 t It 5 15 g e Concentration of formulations 0.25 m i mm 2Q 30 40 50 ig ML ML ML Table 2 None-.- 255 235 210 10 10 LIP 270 270 260 40 LDA 250 240 230 30 Foam stability Grease resistanceML refined g:i"" comm Seed 011 ML 5-6:: 250 260 250 50 33%? 51-10.... 250 250 255 40 v grease s-1 240 235 215 10 met mm $42.... 275 275 270 50 11? 10 20 30 40 50 glass 15 240 240 235 50 235 225 210 250 250 250 Asm the previous example, thel mol ethoxylat e was $28 3 28 practically ineffective as a stabihzer, with or without 250 280 275 50 20 the presence of grease. On the other hand, all of the 2 28 mol and higher ethoxylates showed greatly superior foam stability and grease resistance even by comparison with LIPA and LDA.

EXAMPLE V The above data lndicate superior foam forming and 5 g q com ositio Built formula 9? dodec l foam stabilizing ability at the higher concentration of oammg p n 0 y the formulation as well as greatly superior resistance to benzene Sultanate 45% Sodmm mpoly'phosphate grease 5% SOdllll'Il slhcate, salt cake 37%, foam stabilizer 4% EXAMPLE H1 30 Concentration 0.1% Formulation: Table 5 Foaming composition-20% dodecyl benzene sul- Pa Foam stability Grease resistanee-ML refined Stabilizer concentration 5% cottonseed oil 1 oil Concentration of formulation 0.1% 2 221 llzer Ini- 5 15 film on ltiaall 10 20 30 glass Table 3 Foam stability Grease resistance-ML refined cotton seed oil ML oil 170 170 165 "-55 30 gag 175 110 100 75 30 lizer Ini- 5 15 film on 35 25 85 e tial min min. 10 20 30 40 50 glass ML ML ML 45 The above data demonstrates that in a built formula- ;8 tion, the foam forming ability and stability both with and LDA.-.1 210 210 200 20 Without grease is superior to LIPA.

28 The built formula used represents a commercial formus-oIIIII 150 50 lation. The actual detergent concentration is quite low gj fig 50 and foams normally produced do not stand up well with- S-li::: 185 180 40 out the use of a stabilizer. These formulations are used 185 40 as heavy duty detergents in laundering and cleaning.

55 EXAMPLE VI Formulation:

These data demonstrate that although the initial foam formation at the higher stabilizer concentration is somewhat lower than with LIPA and LDA, the products of the invention imparted excellent foam stability. In ad- Foaming composition. Built formula of Example V.' Concentration 0.25%.

Table 6 di-tion, the ease resistance remained superior. It is 60 significant flit the 1 mol ethoxylated product was no Foam Stablhty Grease gjtigi gj g gf refined M11011 better than, and in fact slightly poorer as a stabilizer by g 232 comparison with the use of no stabilizer, and little or lizer Ini- 5 1 5 film on no better with respect to stability in the presence of the 65 50 glass oil. Compared with the 2 mol and higher ethoxylates this material was unsatisfactory for the purpose, whereas 240 220 20 the 2 mol and higher ethoxylates were definitely superior. 23 240 225 135 3 Formulation: EXAMPLE IV 138 Foaming composition20% dodecyl benzene sulfonate Stabilizer concentration 5% The above data shows a superiority over LIPA in initial foam forming ability and stability, plus equal Formulation concentration 0.25% grease resistance at the higher concentration.

These data demonstrate that the monoisopropanolamine lauric amide ethoxylate is definitely inferior to the corresponding stearic compound and therefore that the C12 fatty acid compound is no better than no Stabilizer and poorer than LIPA or LDA as a foam stabilizer, comparing with the data in Tables 3 and 4.

EXAMPLE VIII Foam stability and resistance to grease with sodium lauryl sulfate as foaming agent.

Basic formula:

20.0% sodium lauryl sulfate 2.5% foam stabilizer 77.5% inerts in lauryl sulfate plus soft water Concentration 0.25%

Table 8 Foam stability Grease resistance-ML refined cotton seed oil ML oil Foam to form stabigrease lizer Ini film on tial min min. 10 glass ML ML ML The above data show that in a foaming composition using a concentrated solution of sodium lauryl sulfate as the detergent, the compounds of the invention were effective as foam stabilizers and in resistance to grease.

It is significant that in all of the comparisons given above, in every case except with the built formulations, in the presence of grease the foam stability with applicants novel composition continued a greater period than 15 minutes, even at high concentrations of oils, whereas with LIPA and LDA, there was no test in which this was attained.

Comparable results are obtainable using other Cl4'-C18 aliphatic carboxylic acids, such as those formed by the oxo process, however, the fatty acids are generally preferred due to their low cost and availability.

The improved foam stabilizers may be used in any desired proportions which may be effective for the purpose, depending on the foaming agent used, water hardness, and other factors. In general, from 0.1 to 20 parts of the ethoxylate may be used with from 5 to 60 parts of the anionic surface active agent in the formulation. The concentration of the formulation itself which is used will vary a great deal depending on the end use of the product.

The foregoing tests clearly demonstrate that a new series of compounds has been developed which have unusual foam stabilizing properties in the presence or absence of grease or oil and which impart improved detergency to anionic detergents. These compounds have excellent emulsifying properties as well. They may be used in cosmetic formulations such as shampoos, hair creams, and vanishing creams. They may also be used in solvent cleaners, dry cleaning and oil well drilling fluids. The solubility may be varied from 0ils0lublc using oleic acid amides, for example, to water-soluble by increasing the length of the ethoxy ether chain.

I claim:

1. As a new composition of matter an ethoxylated aliphatic carboxylic acid amide of isopropanolamine having the following structural formula where R=any aliphatic carboxylic acid radical having 13 or more carbon atoms in the chain and X=2 to 20 inclusive.

2. A foam stabilizer for anionic foaming detergent compositions comprising a Cl4-Cl8 aliphatic carboxylic acid isopropanolamide ethoxylate containing at least 2 111015 of ethylene oxide.

3. A foam stabilizer for anionic foaming detergent compositions which comprises a Cl4-Cl8 fatty acid isopropanolamide ethoxylate containing from 2 to 20 mols of ethylene oxide.

4. A foam stabilizer according to claim 2 wherein the fatty acid is selected from the class consisting of olcic, stearic, palmitic, myristic, linoleic and tall oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,085,706 Schoeller et al. June 29, 1937 2,520,381 Carnes Aug. 29, 1950 2,677,700 Jackson et al. May 4, 1954 2,702,279 Funderburk et a1 Feb. 15, 1955 2,757,143 K-atzman July 31, 1956 2,881,204 Kirkpatrick Apr. 7, 1959 

1. AS A NEW COMPOSITION OF MATTER AN ETHOXYLATED ALIPHATIC CARBOXYLIC ACID AMIDE OF ISOPROPANOLAMINE HAVING THE FOLLOWING STRUCTURAL FORMULA 